SacT. XXXVI. 3. PERIODS OF DISEASES. 5*9 



returns fooner than the period of lunation, it fhews 

 a tendency of the conftitution to inirritability ; that 

 is, to debility, or deficiency of fenforial power, and 

 is to be relieved by fmali dofes of fleet and opium. 



The venereal oigafm of birds and quadrupeds 

 feems to commence, or return about the moft pow- 

 erful luna-tions at the vernal OF autumnal equinoxes; 

 but if it be difappointed of its object, it is faid to 

 recur at monthly periods; in this refpect refembling 

 the female catamenia. Whence it is believed, that 

 women are more liable to become pregnant at or 

 about the time of their catamenia, than at the in- 

 termediate times ; and on this account they are fel- 

 dom much mrftaken in their reckoning of nine lunar 

 periods from the laft menftruation ; the inattention 

 to this may fometimes have been the caufe of fup- 

 pofed barrennefs, and is therefore worth the Obfer- 

 vauon of thofe, who wifli to have children. 



III. We now come to. the periods of difeafed ani- 

 mal actions. The periods of fever-fits, which de- 

 pend on the dated returns of no&urnal cold, are 

 difcufled in Sect. XXXII. 3. Thole, which originate 

 or recur at folar or lunar peiiods, are alfo explain- 

 ed in Section XXXII. 6. Thefe we (hall here enu- 

 merate ; obferving, however, that it is not more fur- 

 prifing, that the influence of the varying attradlions 

 of the fun and moon, mould raife the ocean into 

 mountains, than that -it fhould affect the nice fenfi- 

 bilities of animal bodies ; though the manner of its 

 operation on them is difficult to be underftood. It 

 is probable however, that as this influence gradually 

 leflens during the courfe of the day, or of the luna- 

 tion, or of the year, fome actions of our fyftem be- 

 come lefs and lefs ; till at length a total quiefcence of 

 fome part is induced ; which is the commencement 

 of the paroxyfms of fever, of menftruation, of pain 

 \\ith decreafed action of the affected organ, and of 

 confequent convulfion, 



I. A 



